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// events/846 · BitLocker

Event ID 846Failed to back up recovery information to Entra ID

BitLocker could not back up the recovery password for the volume to Microsoft Entra ID; documented with error 0x80072f9a.

LogMicrosoft-Windows-BitLocker/BitLocker Management
SourceMicrosoft-Windows-BitLocker-API
AreaBitLocker

What to check

On Windows 10 1809 this is fixed by the May 21, 2019 update (KB4497934).

Codes you'll see in this event

CodeMeaning
0x80072f9aSigned-in user cannot read the private key of the provisioning certificate (Windows 10 1809).

Find it with PowerShell

Run on the machine that logs it.

powershell2 lines
Get-WinEvent -FilterHashtable @{ LogName = 'Microsoft-Windows-BitLocker/BitLocker Management'; Id = 846 } -MaxEvents 50 |
    Format-List TimeCreated, Id, Message

Hunt for it in Sentinel or Log Analytics

This works once a data collection rule sends the Microsoft-Windows-BitLocker/BitLocker Management log to your workspace, where it lands in the Event table.

kql5 lines
Event
| where TimeGenerated > ago(7d)
| where EventLog == "Microsoft-Windows-BitLocker/BitLocker Management" and EventID == 846
| project TimeGenerated, Computer, Source, RenderedDescription
| order by TimeGenerated desc

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